U.S. Pat No. 5,254,514, issued Oct. 19, 1993 to Nakagawa, describes the zeolite known as "SSZ-37". The SSZ-37 is described as having a mole ratio of an oxide selected from silicon oxide, germanium oxide and mixtures thereof to an oxide selected from aluminum oxide, boron oxide, gallium oxide, iron oxide and mixtures thereof between 25:1 and 400:1 and having characteristic X-ray diffraction lines. U.S. Pat. No. 5,254,514 does not, however, disclose a high- or all-silica version of SSZ-37.
It is believed that SSZ-37 is related structurally to the zeolite designated NU-87. U.S. Pat. Nos. 5,041,402; 5,178,748 and 5,345,021, all to Casci et al., disclose NU-87. This material is said to contain equal to or less than ten moles of an oxide of aluminum, iron, gallium, boron, titanium, vanadium, zirconium, molybdenum, arsenic, antimony, chromium or manganese per 100 moles of an oxide of silicon or germanium. The typical range of the former group of oxides per 100 moles of silicon or germanium oxide is said to be in the range of 0.1 to 10, for example 0.2 to 7.5.
NU-87 is also disclosed in U.S. Pat. No. 5,102,641, issued Apr. 7, 1992 to Casci et al., with the same mole ratios of oxides as disclosed in the previously mentioned Casci et al. patents.
U.S. Pat. No. 5,254,787, issued Oct. 19, 1993 to Dessau, discloses a catalytic dehydrogenation and/or dehydrocyclization process using a Group VIA or Group VIII metal-containing non-acidic zeolite having the structure of NU-87.